Motion control for work clamping members of automatic sewing machines



Sept. 18, 1951 Filed March 13, 1946 J. RICHTER MOTION CONTROL FOR WORK CLAMPING MEMBERS OF AUTOMATIC SEWING MACHINES 2 Sheets-Sheet l Sept. 18, 1951 J. RICHTER 2,568,205

MOTION CONTROL FOR WORK CLAMPING MEMBERS OF AUTOMATIC SEWING MACHINES Filed March 15, 1946 2 Sheets-Sheet 2 Patented Sept. 18,1951

FOR WORK CLAMPING TOMATIC SEWING MA- MOTION CONTROL MEMBERS OF AU CHINES J ii'i Richter, Zlin,

Czechoslovakia, assignor to Bata, narodni podnik, Zlin, Czechoslovakia Application March 13, 1946, Serial No. 654,092

In Czechoslovakia July 23, 1940 Section 1, Public Law 690, August 8, 1946 Patent expires July 23, 1960 (Orin-104) 4 Claims.

This invention relates to motion control devices for the work clamping members Of automatic sewing machine, such as are used for sewing the closure flaps or various ornamentation, for hemming button-holes, stitching on buttons and like operations, particularly in the manufacture of shoes.

The known arrangements of this type have their work clamping members provided on a special arm which is movable along a straight path in the direction of the longitudinal axis of the bracket of the sewing machine while the other fundamental movement of the arm is a circular one about a fulcrum pin mounted at the end of the arm opposite to that where the clamping members are mounted. In order to obtain a rectilinear movement in this second fundamental direction, that is from left to right or vice versa, it is necessary to provide for compensation of the curvature of the circular path by a simultaneous forward or rearward movement of the arm. The arm-is operated by a disc provided with two curvilinear tracks. The manufacture itself of such discs provided with curvilinear tracks i expensive, and a further disadvantage consists in this that in the. case of a change in the path of movement of the clamping members, for instance in a single direction, it becomes necessary to make use of a different disc even if one of the curved tracks is still conforming to the new path of movement.

The arrangement in accordance with the present invention permits the Work-piece to be fed in all directions by a considerably simpler construction of the motion control mechanism for the clamping members.

Accordingly anpbject of the invention is to provide an arrangement wherein the work clamping members have imp-artedthereto a movement composed of two rectilinear fundamental movements derived from two cam tracks. This arrangement leads to important advantages as compared with all devices of this type known heretofore. The improved device set forth hereinafter is particularly convenient for sewing closure flap shapes whose legs coincide with the directions of the fundamental movements as-- if two flat cams, for instance, are used for operating the clamping member mechanism--it will be sufficient in the majority of cases to change one of. the cams only in order to modify the path of movement. Moreover the improved device permits'modifications in the length and number of stitches to be made within practical limits.

Further advantages andfeatures of the invention are set forth in the following detailed description relating to the accompanying drawings, in which Fig. l is a perspective view of a sewing machine provided with the improved device;

Fig. 2 represents on a larger scale a perspective view of the motion control device proper;

Figs. 3 and 4 illustrate in elevation and plan views respectively the means for converting the longitudinal movement into a transverse movement in the motion control device for the work claimping members; and

Fig. 5 is a detail view in top plan of a portion of the mechanism. a

The base plate I of the machine carries a hollow upper bracket 2 (Fig. 1) which encloses, and has mounted therein, the driving mechanism of the needle 3, and a lower bracket 4 in which a part of the motion control for the clamping members is mounted. Operative motion is imparted to the needle 3 in a manner known per se from an electric motor (not shown), which is mounted under the base plate I of the machine and drives an idle pulley and a fixed pulley on the main shaft, through an assembly of further shafts and gears. From the main shaft (not shown) motion is transmitted through gears to a transverse shaft 5 (Fig. 2) on which two flanges 8 are secured, one on each side of the bracket 2. The driving cams 6 and l of the motion control device for the clamping members are removably mounted on the flanges 8. The upper clamping member 9 is secured to a stirrup it! and the lower clamping member H is secured by a pinand-slot connection H to a guide rod l2. The stirrup I0 and guide rod 12 are secued to a slide l3 so that the two members 9 and H form a movable unit. The guide rod [2 of the lower clamping member H is guided in a longitudinal direction with respect to the bracket axis in a guide sleeve M which is secured on a rack l5 transversely slidable in a dual leg guide it which is fixed on the lower bracket 4 of the machine. To provide the guided transverse motion of rack IS, the latter includes guide pins 38, 38 extending laterally from each side thereof and which slide in correspondingly sized apertures 39, 39' provided in each leg of the guide It. A spring I! urges a roller 20 carried by one of the arms of a double-armed lever I8 against the cam l. The double-armed lever I8 is rotatably mounted on a shaft 19 held in the bracket 2 of the machine, and has its other arm provided with a longitudinal slot 2| in which a pin 22 is adjustably held. On the projecting end of the pin 22 a link 23 is freely mounted, whose opposite end is connected to the slide l3. The cam 6 engages with a roller 24 provided on a double armed lever 25, which too is rotatably mounted on the shaft l9 and whose other arm is provided with a slot 26. In the slot 26 there is fixed by means of an adjustable pin 27 one end of a link 28 the other end of which terminates in a sleeve connection to pin 29 of a toothed rack 30 guided in the lower bracket 4 of the machine. The teeth of the rack 30 mesh with a pinion 3| (Figs. 3 and 4) which in turn meshes with the transversely slidable rack l in the guide IS. The bracket 2 of the machine has fastened thereon a leaf spring 32 which exerts pressure against pin 38' and hence also against gear rack l5 to limit the lost motion of the mechanism and to indirectly also maintain the roller 24 on double-armed lever 25 in engagement with the cam 6. That is to say, with the parts in the position shown in Fig. 2, the pressure of spring 32 working through the rack and pinion 3i urges rack 39 and link 28 in a direction away from cam 6 thus urging lever counterclockwise so that roller 24 maintains its contact with the low portion of the cam. When the high portion of the cam 8 reaches roller 24, lever 25 is rocked clockwise causing link 28 and rack to move rearwardly. This rotates pinion 3| clock wise and shifts rack l5 which carries the guide M to the left against the counterpressure exerted by spring 32. The upper clamping member 9 is urged toward the lower member II by a spring 33 secured to the slide [3. For lifting the upper member 9 to permit the work piece to be inserted between the two clamping members a doublearmed lever 34 (Fig. 1) is provided. The lever 34 which is rotatable about a pivot pin 35, carries a pin 36 extending under the stirrup It] cf the upper member 9 and is operated by hand or foot. The slots 3'. at the ends of the clamping members correspond in shape to the rectilinearly effected motion of the clamping members as determined by the configuration of cam plates 6 and l, and also to the shape of the closure flaps to be sewed on.

The above described device operates as follows:

Before starting the machine the article to be sewed is placed between the clamping members 9 and II. For this purpose the upper member 9 is lifted by depressing the rear end of lever 36 (Fig. 1), the article is inserted between the two clamping members and when the lever 34 is again released the pressure of the spring 33 forces the upper member 9 against the lower member ll, whereby the article is securely clamped between the members. Now the machine is started so that the needle performs its sewing movement downwardly and upwardly, While the members 9 and H feed the work-piece in accordance with the desired shape of sewing. During this operation the shaft 5 rotates together with the cams 6 and l. The resultant movement of the clamping members is composed of two rectilinear movements, these being a movement longitudinally of the bracket 2 and a movement transverse to the machine bracket 2. In the example shown in the drawing the longitudinal movement is produced by the cam I (Fig. 2) which through the double-armed lever l8 and link 23 acts upon the slide [3 for the stirrup IE] and the guide rod 12 of the clamping members. The transverse movement derived from the cam 6 through the above described mechanism 25, 23, 3e, 3|, I5 is transmitted by the guide sleeve M to the guide rod I2. The link 23 associated with slide I 3 is slidable in a transverse direction on the end extension of the pin 22, so that in the guide sleeve the transverse and longitudinal movements are combined into a resultant movement of the clamping members. In the illustrated embodiment, the cam plates 6 and 1 have a configuration such that the clamping members will describe a rectangular path generally coincident with the edges of the rectangular slot 31. Such an arrangement would be used for stitching on rectangular closure flaps around the edges of the flap. The machine can be adapted to stitch on closure flaps of other configurations such as triangular, for example, by replacing the illustrated cams 6 and 1 with others of different configuration such that the clamping members 9 and H would describe a triangular path. In such case the clamping members 9 and H now illustrated would of course be replaced with others having triangularly configured slots. A change only in the length of the longitudinal and transverse movements of the clamping members may be obtained by shifting the pins 22 and 27 in the slots 2| and 26. The number of stitches may be changed by effecting a, change in speed in the variable speed transmission between the main shaft and the shaft 5.

The embodiment as above described and shown in the drawing is merely an example of carrying out the invention and may be modified in various respects within the scope of the appended claims without departing from the essence of the invention.

What I claim is:

1. In a motion control device for the upper and lower work clamping members of sewing machines, a slidable support common to said members and securing the same in superposed relation, a guide associated with said lower clamping member for guiding said members and said support in a direction of motion longitudinally of the guide, means supporting said guide for motion in a direction transverse to the longitudinal axis thereof to thereby efiect a corresponding motion of said clamping members, means actuating said slidable support longitudinally of said guide, and means actuated in timed relation with said support actuating means for imparting said transverse movement to said guide.

2. In a motion control for the upper and lower work clamping members of sewing machines, a slidable support common to said members and securing the same in superposed relation, a guide associated with said lower clamping member for guiding said members and said support in a direction of motion longitudinally of said guide, a rack gear supporting and secured to said guide and movable in a direction transverse to the longitudinal axis of the guide to thereby impart a cor responding movement to said guide and clamping members, a first cam drive coupled to said slidable support for actuating the latter and hence said clamping members longitudinally of said guide, and a second cam drive including gearing meshed with said rack gear and operated in timed relation with said first cam drive for imparting the said transverse movement to said gear and guide.

3. In a motion control for the upper and lower work clamping members of sewing machines, a slidable support common to said members, said upper clamping member being connected to said support by an intermediate stirrup and said lower clamping member being connected to said support by a guide rod, a guide sleeve forming a bearing for said guide rod, a rack gear supporting and secured to said sleeve and movable in a direction transverse to the longitudinal axis of said sleeve to thereby impart a corresponding movement to said sleeve and guide rod, a first cam drive coupled to said slidable support for actuating the latter and guide rod and hence also said clamping members longitudinally of'said guide sleeve, and a second cam drive including gearing meshed with said rack gear and operated in timed relation with said first cam drive for imparting the said transverse movement to said gear and guide sleeve.

4. A motion control device as defined in claim 3 wherein said first cam drive includes a cam track, a link connected to said slidable support and a double arm lever transmitting motion from said track to said link, and said second cam drive 6 includes a second cam track, a pinion meshed with said rack gear, a second rack gear meshed with and driving said pinion and a double arm lever transmitting motion from said second cam track to said second rack gear. v

JIRI RICHTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,998,885 Rosenthal Apr. 23, 1935 2,230,466 Meredith et a1 Feb. 4. 1941 

